When it comes to concerns about heart health, coffee lovers have some basic questions: Is there a link between coffee consumption and cardiovascular disease? Will coffee increase blood pressure (hypertension)? Is it safe for those who already have high blood pressure? What about cholesterol levels?
The good news is that coffee is safe. Regarding hypertension, which is a major risk factor for heart disease, while coffee and caffeine can give blood pressure an immediate slight increase, this change is temporary and is not considered harmful. In the case of cholesterol, filtered coffee which is the brew of choice for most Canadian consumers may actually have a positive effect on “good” cholesterol.
In fact, following decades of exhaustive research, coffee has been given a green light for those concerned about heart health. The Heart and Stroke Foundation of Canada, for example, states that drinking up to four cups of coffee a day is not linked to serious health problems.(REF)
Perhaps more than any other area, the effect of coffee and caffeine on heart health has been the subject of extensive and sometimes conflicting research. This research has focussed on coronary heart disease (CHD) and more specifically on blood pressure (hypertension) and cholesterol levels.
Several major research study projects have examined the connection between coffee consumption and CHD with all essentially concluding that coffee is entirely safe and not a risk factor. For example, a landmark Harvard University team study published in the New England Journal of Medicine (reference link) followed 45,000 men and looked at various cardiovascular risk factors. It concluded that coffee consumption does not cause an increased risk of CHD.
Similar conclusions have been shown with women as well. The Nurses Health Study, which with 85,000 subjects is the largest study ever conducted on women, also concluded that there is not evidence that coffee drinkers have a greater risk of developing CHD.
In fact the Scottish Heart Health Study of 10,000 men and women, published in the Journal of Epidemiology & Community Health (research link) in 1993 found that coffee drinkers have a lower rate of heart disease.
While there is a lingering negative perception regarding the effect of coffee and caffeine on blood pressure, significant and respected studies have conclusively disproved this.
In 1988, one of Canada’s leading cardiologists, Dr. Martin Myers, published a groundbreaking, internationally recognized study in the Archives of Internal Medicine (link to abstract in Research highlights), concluding that caffeine does not cause a long term increase in blood pressure. Myers’ work showed that individuals who are not regular coffee drinkers may experience a slight increase when first exposed to caffeine. However, blood pressure levels quickly return to baseline as tolerance develops very quickly, within two to three days.
More recently, a massive landmark study of 155,000 American women showed similar results to Myers’ work. Conducted by a research team at Boston’s Brigham and Women’s Hospital, a study published in the Journal of the American Medical Association (link to abstract in Research highlights) concluded that habitual coffee consumption is not associated with increased risk of hypertension, finding also that there is a connection between cola consumption and high blood pressure.
It is noteworthy that research has also indicated that when individuals stop consuming coffee there is no effect on blood pressure, according to a study published in the American Journal of Clinical Nutrition (link to abstract in Research highlights) in 1991.
In the case of cholesterol, some key research has actually shown that coffee, specifically filtered coffee, can have a positive role in controlling cholesterol. Published in the Journal of the American Medical Association, a major study using filtered coffee concluded that consumption can lead to a small increase in levels of high density lipoprotein or “good” cholesterol which is seen to lower the risk for coronary heart disease. (ref)
Some research, including a study published in the British Medical Journal in 1996, indicates that boiled coffee (which is not filtered) may raise blood cholesterol levels because it contains cafestol and kahweol, which are fat-soluable substances. However, it is generally agreed that negative effects are only seen with large amounts (more than five cups daily) of quite strong coffee.